[72] 编辑距离

/**
 * @param {string} word1
 * @param {string} word2
 * @return {number}
 */
var minDistance = function (word1, word2) {
  const len1 = word1.length;
  const len2 = word2.length;
  const matrix = Array.from(Array(len1 + 1), () => new Array(len2 + 1));
  for (let i = 0; i <= len1; i++) {
    matrix[i][0] = i;
  }
  for (let j = 1; j <= len2; j++) {
    matrix[0][j] = j;
  }
  for (let i = 1; i <= len1; i++) {
    for (let j = 1; j <= len2; j++) {
      if (word1[i - 1] === word2[j - 1]) {
        matrix[i][j] = matrix[i - 1][j - 1];
      } else {
        matrix[i][j] = Math.min(matrix[i - 1][j - 1], matrix[i][j - 1], matrix[i - 1][j]) + 1;
      }
    }
  }
  return matrix[len1][len2];
};